// R_planes.c
// $Revision: 491 $
// $Date: 2009-05-30 01:10:42 +0300 (Sat, 30 May 2009) $

#include "h2stdinc.h"

#ifndef RENDER3D

#include "doomdef.h"
#include "r_local.h"

// MACROS ------------------------------------------------------------------

// TYPES -------------------------------------------------------------------

// EXTERNAL FUNCTION PROTOTYPES --------------------------------------------

// PUBLIC FUNCTION PROTOTYPES ----------------------------------------------

// PRIVATE FUNCTION PROTOTYPES ---------------------------------------------

// EXTERNAL DATA DECLARATIONS ----------------------------------------------

extern byte		*ylookup[MAXHEIGHT];
extern int		columnofs[MAXWIDTH];

// PUBLIC DATA DEFINITIONS -------------------------------------------------

// Sky mapping
int			skytexture;
int			skyflatnum;
int			skytexturemid;
fixed_t			skyiscale;

planefunction_t		floorfunc, ceilingfunc;

// Opening
visplane_t		visplanes[MAXVISPLANES], *lastvisplane;
visplane_t		*floorplane, *ceilingplane;
short			openings[MAXOPENINGS], *lastopening;

// clip values are the solid pixel bounding the range
// floorclip starts out SCREENHEIGHT
// ceilingclip starts out -1
short			floorclip[SCREENWIDTH];
short			ceilingclip[SCREENWIDTH];

// spanstart holds the start of a plane span
// initialized to 0 at start
int			spanstart[SCREENHEIGHT];
int			spanstop[SCREENHEIGHT];

// texture mapping
lighttable_t		**planezlight;
fixed_t			planeheight;

fixed_t			yslope[SCREENHEIGHT];
fixed_t			distscale[SCREENWIDTH];
fixed_t			basexscale, baseyscale;
fixed_t			cachedheight[SCREENHEIGHT];
fixed_t			cacheddistance[SCREENHEIGHT];
fixed_t			cachedxstep[SCREENHEIGHT];
fixed_t			cachedystep[SCREENHEIGHT];

// PRIVATE DATA DEFINITIONS ------------------------------------------------

// CODE --------------------------------------------------------------------

//==========================================================================
//
// R_InitSkyMap
//
// Called whenever the view size changes.
//
//==========================================================================

void R_InitSkyMap(void)
{
	skyflatnum = R_FlatNumForName("F_SKY1");
	skytexturemid = 200*FRACUNIT;
	skyiscale = FRACUNIT;
}

//==========================================================================
//
// R_InitPlanes
//
// Only at game startup
//
//==========================================================================

void R_InitPlanes(void)
{
}

//==========================================================================
//
// R_MapPlane
//
// Globals used: planeheight, ds_source, basexscale, baseyscale,
// viewx, viewy.
//
//==========================================================================

void R_MapPlane(int y, int x1, int x2)
{
	angle_t angle;
	fixed_t distance, length;
	unsigned idx;

#ifdef RANGECHECK
	if (x2 < x1 || x1 < 0 || x2 >= viewwidth || (unsigned)y > viewheight)
	{
		I_Error("R_MapPlane: %i, %i at %i", x1, x2, y);
	}
#endif

	if (planeheight != cachedheight[y])
	{
		cachedheight[y] = planeheight;
		distance = cacheddistance[y] = FixedMul(planeheight, yslope[y]);
		ds_xstep = cachedxstep[y] = FixedMul(distance, basexscale);
		ds_ystep = cachedystep[y] = FixedMul(distance, baseyscale);
	}
	else
	{
		distance = cacheddistance[y];
		ds_xstep = cachedxstep[y];
		ds_ystep = cachedystep[y];
	}

	length = FixedMul(distance, distscale[x1]);
	angle = (viewangle+xtoviewangle[x1])>>ANGLETOFINESHIFT;
	ds_xfrac = viewx+FixedMul(finecosine[angle], length);
	ds_yfrac = -viewy-FixedMul(finesine[angle], length);

	if (fixedcolormap)
	{
		ds_colormap = fixedcolormap;
	}
	else
	{
		idx = distance >> LIGHTZSHIFT;
		if (idx >= MAXLIGHTZ)
		{
			idx = MAXLIGHTZ-1;
		}
		ds_colormap = planezlight[idx];
	}

	ds_y = y;
	ds_x1 = x1;
	ds_x2 = x2;

	spanfunc();	// high or low detail
}

//==========================================================================
//
// R_ClearPlanes
//
// At begining of frame
//
//==========================================================================

void R_ClearPlanes(void)
{
	int i;
	angle_t angle;

	// Opening / clipping determination
	for (i = 0; i < viewwidth; i++)
	{
		floorclip[i] = viewheight;
		ceilingclip[i] = -1;
	}

	lastvisplane = visplanes;
	lastopening = openings;

	// Texture calculation
	memset(cachedheight, 0, sizeof(cachedheight));
	angle = (viewangle - ANG90)>>ANGLETOFINESHIFT;	// left to right mapping
	// Scale will be unit scale at SCREENWIDTH/2 distance
	basexscale = FixedDiv(finecosine[angle], centerxfrac);
	baseyscale = -FixedDiv(finesine[angle], centerxfrac);
}

//==========================================================================
//
// R_FindPlane
//
//==========================================================================

visplane_t *R_FindPlane(fixed_t height, int picnum,
			int lightlevel, int special)
{
	visplane_t *check;

	if (picnum == skyflatnum)
	{ // All skies map together
		height = 0;
		lightlevel = 0;
	}

	for (check = visplanes; check < lastvisplane; check++)
	{
		if (height == check->height &&
		    picnum == check->picnum &&
		    lightlevel == check->lightlevel &&
		    special == check->special)
			break;
	}

	if (check < lastvisplane)
	{
		return check;
	}

	if (lastvisplane - visplanes == MAXVISPLANES)
	{
		I_Error("R_FindPlane: no more visplanes");
	}

	lastvisplane++;
	check->height = height;
	check->picnum = picnum;
	check->lightlevel = lightlevel;
	check->special = special;
	check->minx = SCREENWIDTH;
	check->maxx = -1;
	memset(check->top, 0xff, sizeof(check->top));
	return check;
}

//==========================================================================
//
// R_CheckPlane
//
//==========================================================================

visplane_t *R_CheckPlane(visplane_t *pl, int start, int stop)
{
	int intrl, intrh;
	int unionl, unionh;
	int x;

	if (start < pl->minx)
	{
		intrl = pl->minx;
		unionl = start;
	}
	else
	{
		unionl = pl->minx;
		intrl = start;
	}
	if (stop > pl->maxx)
	{
		intrh = pl->maxx;
		unionh = stop;
	}
	else
	{
		unionh = pl->maxx;
		intrh = stop;
	}

	for (x = intrl; x <= intrh; x++)
	{
		if (pl->top[x] != 0xff)
		{
			break;
		}
	}

	if (x > intrh)
	{
		pl->minx = unionl;
		pl->maxx = unionh;
		return pl;	// use the same one
	}

	// make a new visplane
	lastvisplane->height = pl->height;
	lastvisplane->picnum = pl->picnum;
	lastvisplane->lightlevel = pl->lightlevel;
	lastvisplane->special = pl->special;
	pl = lastvisplane++;
	pl->minx = start;
	pl->maxx = stop;
	memset(pl->top, 0xff, sizeof(pl->top));

	return pl;
}

//==========================================================================
//
// R_MakeSpans
//
//==========================================================================

void R_MakeSpans(int x, int t1, int b1, int t2, int b2)
{
	while (t1 < t2 && t1 <= b1)
	{
		R_MapPlane(t1, spanstart[t1], x - 1);
		t1++;
	}
	while (b1 > b2 && b1 >= t1)
	{
		R_MapPlane(b1, spanstart[b1], x - 1);
		b1--;
	}
	while (t2 < t1 && t2 <= b2)
	{
		spanstart[t2] = x;
		t2++;
	}
	while (b2 > b1 && b2 >= t2)
	{
		spanstart[b2] = x;
		b2--;
	}
}

//==========================================================================
//
// R_DrawPlanes
//
// At the end of each frame
//
//==========================================================================

void R_DrawPlanes(void)
{
	visplane_t *pl;
	int light;
	int x, stop;
	int angle;
	byte *tempSource;
	byte *dest;
	int count;
	fixed_t frac, fracstep;

#ifdef RANGECHECK
	if (ds_p - drawsegs > MAXDRAWSEGS)
	{
		I_Error("R_DrawPlanes: drawsegs overflow (%i)", ds_p - drawsegs);
	}
	if (lastvisplane - visplanes > MAXVISPLANES)
	{
		I_Error("R_DrawPlanes: visplane overflow (%i)", lastvisplane - visplanes);
	}
	if (lastopening - openings > MAXOPENINGS)
	{
		I_Error("R_DrawPlanes: opening overflow (%i)", lastopening - openings);
	}
#endif

	for (pl = visplanes; pl < lastvisplane; pl++)
	{
		if (pl->minx > pl->maxx)
		{
			continue;
		}
		if (pl->picnum == skyflatnum)
		{ // Sky flat
			dc_iscale = skyiscale;
			dc_colormap = colormaps;// sky is allways drawn full bright
			dc_texturemid = skytexturemid;
			for (x = pl->minx; x <= pl->maxx; x++)
			{
				dc_yl = pl->top[x];
				dc_yh = pl->bottom[x];
				if (dc_yl <= dc_yh)
				{
					angle = (viewangle + xtoviewangle[x])>>ANGLETOSKYSHIFT;
					dc_x = x;
					dc_source = R_GetColumn(skytexture, angle);
					count = dc_yh - dc_yl;
					if (count < 0)
						return;
#ifdef RANGECHECK
					if ((unsigned)dc_x >= SCREENWIDTH || dc_yl < 0 || dc_yh >= SCREENHEIGHT)
						I_Error ("R_DrawColumn: %i to %i at %i", dc_yl, dc_yh, dc_x);
#endif
					dest = ylookup[dc_yl] + columnofs[dc_x]; 
					fracstep = 1;
					frac = (dc_texturemid>>FRACBITS) + (dc_yl-centery);		
					do
					{
						*dest = dc_source[frac];
						dest += SCREENWIDTH;
						frac += fracstep;
					} while (count--);
				//	colfunc ();
				}
			}
			continue;
		}

		// Regular flat
		tempSource = (byte *) W_CacheLumpNum(firstflat + flattranslation[pl->picnum], PU_STATIC);
		switch (pl->special)
		{
		case 25: case 26: case 27: case 28: case 29: // Scroll_North
			ds_source = tempSource;
			break;
		case 20: case 21: case 22: case 23: case 24: // Scroll_East
			ds_source = tempSource + ((63 - ((leveltime>>1) & 63))<<(pl->special - 20) & 63);
			//ds_source = tempSource+((leveltime>>1)&63);
			break;
		case 30: case 31: case 32: case 33: case 34: // Scroll_South
			ds_source = tempSource;
			break;
		case 35: case 36: case 37: case 38: case 39: // Scroll_West
			ds_source = tempSource;
			break;
		case 4: // Scroll_EastLavaDamage
			ds_source = tempSource + (((63 - ((leveltime>>1) & 63))<<3) & 63);
			break;
		default:
			ds_source = tempSource;
		}
		planeheight = abs(pl->height - viewz);
		light = (pl->lightlevel >> LIGHTSEGSHIFT) + extralight;
		if (light >= LIGHTLEVELS)
		{
			light = LIGHTLEVELS-1;
		}
		if (light < 0)
		{
			light = 0;
		}
		planezlight = zlight[light];

		pl->top[pl->maxx + 1] = 0xff;
		pl->top[pl->minx - 1] = 0xff;

		stop = pl->maxx + 1;
		for (x = pl->minx; x <= stop; x++)
		{
			R_MakeSpans(x, pl->top[x - 1], pl->bottom[x - 1],
					pl->top[x], pl->bottom[x]);
		}
		Z_ChangeTag(tempSource, PU_CACHE);
	}
}

#endif	/* !RENDER3D */

